IMO game_save() is not really intended for any real project, it's just a quick and newbie friendly way (see following limitations) to realize a let's say quicksave and -load feature (which is supposed to save all entity positions and states in a level).
It's a really old command from times where you basically could not create anything but entities dynamically, which is why calling panel or text (/ ...) create instructions break the game_load function. I'd say only use that function on a very simple project which doesn't generate anything dynamically.
Otherwise, do as FoxHound said:
If you simply want to save an array of string don't use the game save but write a txt file and then load back up as needed. The game save setup from 3dgs is designed to load a whole world. Way to complicated and time consuming compared to a simple text file.
When it comes to saving your game progress just save some variables into a text file which describe the player's progress sufficiently, then load those variables and create a corresponding game state when necessary.
